1. Field of the Invention
The present invention discloses a tool for securing threaded inserts. More specifically, the present invention discloses a tool and method for accurately and consistently placing threaded rivet inserts into holes in metal or other material designed to receive the inserts. The present invention discloses a threaded shaft used in conjunction with a sleeve that provides consistency and accuracy.
2. Prior Art
Rivets have become common in all manufacturing industries. They have come to serve more than one function. Rivets are often used to hold two or more pieces of sheet metal or other material together but serve other functions as well. Rivets are generally cylindrical having a flanged end. The cylindrical insert portion of the rivet is placed within a hole designed to receive the rivet insert. A tool is then used to form a flange on the opposite side of the hole from the pre-existing flange. These flanges form collars on either side of the hole into which the rivet is inserted. The collars hold the rivet in place and can hold two or more pieces of sheet metal or other similar flat material together when captivated between the collars.
While some rivets do not have a hollow interior of the cylindrical portion, others do. Many rivets are designed so that a hollow cylindrical insert portion is threaded on the inside. This threading allows screws and bolts to be attached to the rivet after it is in place. These threaded rivets have become common, especially in the automotive industry. They may be used in conjunction with bolts screws and other threaded shafts to attach a variety of materials to the sheet metal from which automobile bodies are typically formed. Those skilled in the art of auto body manufacture, assembly and repair are very familiar with threaded rivets.
A blind threaded rivet has a flanged head, a thin, walled sleeve portion and a nut and is designed to be inserted into an opening in a wall or sheet. The advantage of blind rivets is that access to only one side of the opening in the wall or sheet is necessary. Fixing of a blind rivet is accomplished by deforming the sleeve portion to a bulge so that the wall or sheet is clamped between the head and bulge or flange of the rivet. For performing this rivet setting operation, a threaded drift is provided at the end of an inserting shaft which is inserted into a rivet setting tool. The threaded drift of the shaft is screwed into the nut portion of the rivet so as to engage the same and pull the nut in the direction of the wall or sheet. Only the unthreaded sleeve of the cylindrical part of the rivet is compressed into a second flanged collar. The threaded nut of the rivet is unchanged.
Riveting tools may be pneumatically powered or manually powered. Tools designed for blind rivets have a bore into which a shaft is inserted and locked into place. When the riveting tool is activated, the riveting shaft is drawn further into the bore of the riveting tool. In the case of threaded blind rivets, the threaded drift portion of the inserting shaft which is engaged to the nut portion of the rivet is drawn toward the riveting tool. The portion of the riveting tool directly adjacent to the bore into which the shaft is inserted engages the head of the rivet. The portion of the tool engaging the head and the motion of the shaft engaging the nut portion of the rivet causes the action which fixes the rivet by deforming the sleeve portion of the rivet into a flange.
There are a wide variety of different types of riveting tools. All riveting tools designed for use with threaded blind rivets have a bore into which the inserting shaft is to be inserted. These threaded blind rivet inserting tools also have a flat face surrounding the bore designed to engage the head of the rivet. Combination of the newly formed flange and the head of the rivet hold the rivet in position within the hole into which it was inserted. The combination of head and new flange may also be used to hold two or more flat pieces of metal or other material together.
Practically every automobile on the road today has many of these threaded rivets. It has, therefore, become very important for automobile repair shops to be capable of replacing these threaded rivets. Auto repair shops, however, generally do not posess the same type of pneumatic equipment that the manufacturers use to install these threaded rivets. Instead, these repair shops generally use less expensive, hand operated rivet inserting tools. While these hand held tools are significantly less expensive than the equipment used by manufacturers, they are much more difficult to use. Also, hand held rivet insert tools generally do not consistently apply the same amount of pressure to subsequent rivets when inserting them. This inaccuracy decreases the value of the repair work.
Another problem with threaded blind rivet insert tools is that too much force may be applied to the threaded blind rivet. This may result in damage to the threaded nut portion of the rivet. If this occurs the rivet is useless, and often quite difficult to remove from the hole into which it was inserted. At the same time, it is important to apply a sufficient amount of force so that the sleeve portion of the rivet creates an effective flange.
It is also desirable to provide a means of fixing a threaded blind rivet without damaging the nut portion of the rivet.
It is also desirable to provide a means of fixing a blind threaded rivet securely by sufficiently forming a flange.
It is therefore desirable to provide a rivet insert tool that will consistently apply the same force to subsequent inserted rivets.
The present invention combines a threaded rivet insert shaft with a sleeve designed to provide uniformly fixed inserted blind threaded rivets. The combination shaft and sleeve may be used with either pneumatic, air pressure or hand operated rivet inserting tools. The invention securely inserts rivets having a uniform depth into the holes designed to receive the rivets.
The use of threaded insert shafts is well known in the art of threaded rivets. These insert shafts have two ends. One end is comprised of a drift having threading to which a threaded insert is attached. The other end is smooth and unthreaded and designed to attach to a riveting tool. A threaded rivet is threaded onto the drift portion of the shaft. It is threaded onto the shaft in such a way so that the head faces the smooth stem end of the shaft, and the cylindrical portion of the rivet having the sleeve and nut portions of the rivet is on the other side of the head from the smooth stem of the shaft.
Ideally, the tool facing end of the threaded drift of the insert shaft is flush with the point where the sleeve portion of the rivet ends and the nut portion of the rivet begins. Unfortunately, the tool facing end of the threaded drift when flush with the point at which the sleeve portion ends is located within the cylindrical portion of the rivet. This obstructs the view, and makes it very difficult to accurately position the threaded drift. When the rivet is not accurately positioned on the shaft, the rivet may be under or over compressed resulting in either a damaged rivet, or one that is too loose, neither of which is desirable.
The present invention overcomes this difficulty. The rivet inserting shaft is sheathed with a metal sleeve. The metal sleeve has a bore running through it having two different diameters. These two different diameters correspond to the different diameters of the smooth portion of the inserting shaft and the threaded drift portion of the inserting shaft. The larger diameter region of the bore, designed to accommodate both the smooth and threaded drift portions of the shaft has a depth equal to the length of the sleeve portion of the rivet. The remaining, smaller diameter portion of the bore through the sleeve has a diameter large enough to accommodate the smooth stem of the inserting shaft but too small to allow the threaded drift portion of the shaft to enter it.
The smooth stem of the inserting shaft extending out of the smaller diameter portion of the bore in the sleeve is then inserted into a rivet inserting tool. The inserting shaft is inserted as far as possible into the inserting tool, so that the head of the rivet engages one end of the sleeve and the flat face portion of the inserting tool engages the other end of the sleeve. The rivet is then inserted into the hole to which it is to be fixed.
Instead of the user threading the insert onto the shaft guessing at which point the tool facing end of the threaded drift of the shaft is flush with the point at which the nut of the rivet begins, the sleeve automatically measures this distance. The rivet is placed so that the nut portion of the rivet engages the threaded drift portion of the inserting shaft and the rivet head is flush with the tool facing end of the threaded drift portion of the shaft. The sleeve is then placed over the smooth portion of the shaft prior to the smooth portion being inserted into the riveting tool. The depth of the larger portion of the bore hole is greater than the length of the unthreaded sleeve portion of the cylindrical part of the rivet.
The distance to which the inserting shaft is retracted into the inserting tool is determined by the amount of pressure applied to the item by the tool. This prevents overcompression of the rivets which causes damage to the nut portion of the rivet. This also prevents undercompression of the rivets which results in a poor flange. A poor flange causes the rivet to be loose. This makes it ineffective at holding two or more flat surfaces together. This also results in a threaded rivet of poor quality which may be unuseable. A poorly compressed rivet will have to be removed. This can be inconvenient and time consuming.
The present invention also has the significant advantage of being capable of being retrofitted to existing rivet equipment. No additional equipment needs to be acquired in order to add the present invention to existing riveting systems. In addition to being cost efficient, this also makes the invention easy to use. Very little instruction is needed for one skilled in the art of riveting to add to the present invention to existing equipment.
The present invention is relatively easy and inexpensive to manufacture. The low cost and ease of use of the invention makes it highly attractive to those skilled in the art of riveting.
It is therefore an object of the present invention to provide a method for inserting a threaded blind rivet without overcompressing the rivet.
It is another object of the present invention to provide a means of inserting a threaded blind rivet without failing to properly compress said rivet, thereby forming an unuseable rivet.
It is therefore an object of the present invention to provide a reliable method of applying consistent pressure to subsequent inserted rivets.
Another object of the present is to provide an improved tool that may be used with minimal instruction.
Yet another object of the present invention is to provide a system for improving rivet application A related object of the present invention is to improve the consistency of rivet application.
A base object of the present invention is to provide an improved repair tool for use with vehicles or the like.